Anthropic can POST to your HTTPS endpoint when a Managed Agents resource changes state — an alternative to holding an SSE stream or polling. Payloads are thin (event type + resource IDs only); on receipt, fetch the resource for current state. Every delivery is HMAC-signed. Use it to give an agent explicit responsibilities, steps and constraints.
All endpoints require x-api-key and anthropic-version: 2023-06-01 headers. Managed Agents endpoints additionally require the anthropic-beta header. Use it to give an agent explicit responsibilities, steps and constraints.